No drive to wheels

[Bert_W164]

Hi All,

I bought a W plate Clk230 yesterday. As I was driving in town couldn't test the cruise control.

I bought the car, went on the motorway,thought ahhh time for cruise control. Switched it on, set limit to 60mph, heard a gear change, but it was in fact a disengage of a gear.

I had no drive, gas pedal equated to free revving. +/- done nothing.

It was very alarming, I pulled into the hard shoulder, restarted engine and done away with c cruise control and everything was fine.

I've driven 100 miles and it's not done it,so it appears the problem is related to cruise control.

Luckily I have a Mercedes Technician in the family,but won't be able to have the car on Star until a couple of weeks.

Any guesses as to what the issue could be?

 

[nb_racing]

It wasn't in speed limiter mode was it? (don't wish to insult you!)

 

[Benzowner]

I think you probably engaged speed limiter rather than cruise, if a light came on, on the cruise control stalk, that would be what you did. To engage cruise, you only need to set the desired speed with your foot and the raise the cruise control up to disengage push forward, to reengage pull back and to slow woth cruise on move the stalk down. You can also increase speed by raising the stalk. If you push the end of the cruise control, that engages the speed limiter.

 

[Bert_W164]

It was limited to 60 but fell to 40 still had no drive.

Also just went to put fuel in, selected neutral then D and again no drive.

But it's odd because I can go from R to D and the drive is there. My brother tells me it may be the gearbox control unit or selector unit. I'll get it on star.

 

[Stratman]

It'll be worth having the transmission fluid checked too, both for level and condition.

 

[panason1c]

Selecting the speed limiter (instead of cruise) would not result in loss of drive.....More likely to be a gearbox 'valve block' or 'speed sensor/conductor plate' problem.

Star will read the stored codes stored to confirm.

 

[Bert_W164]

Cheers. Won't be able to access Star till next Saturday, will try to reduce how much I use the car till then.

 

[Bert_W164]

Thanks all, just to clarify it's not slipping. I hear the gear disengage and a restart of engine seems to fix the problem.

Its happened 3 times within 200 miles. I think the CC was just a coincidence.

 

[Bert_W164]

Update:

Star saw a whole bunch of previous codes but nothing current.

We proceeded to change the oil and the drain plug has never been used/rusted so couldn't undo it.

Proceeded to drain it via the sump pan and a bolt broke, rusted.

However since clearing the codes and giving it a service (engine oil was jet black) the car is a lot happier, pulls harder and the gearbox didn't give any issues.

Back to Mercs for the drain and possibly tapping of all the bolts!

It a abundantly clear no one has changed the gearbox oil. Star didn't see any current problems and the mileage is genuine.

If the car needs a new box, so be it. The engine pulls strongly and it's worth the money to me. For the most part the underside of the car is clean, suspension is in good condition so this is worth restoring.

 

[Bert_W164]

Final update:

Uses a chisle to get the sump plug off. Hardly any oil inside...probably 1.5L came out of near black liquid.

Unfortunately sump bolts were seized and we hadn't ordered brackets anticipating for broken bolts so in the interim we used around 3L of transmission fluid just to flush the system. The amount of thick near black oil that came out was amazing.

Refilled it with 4L...

The difference is day and night. I now have a silky smooth gearbox which pulls strong in every gear without throwing its toys out the pram.

Fuel consumption has improved too, as I'm no longer sitting in W mode avoiding first and the box is no longer selecting some weird gears to get along.

It's transformed the car.

We still need to remove some more bolts, clean the sump pan and replace the filter/gasket but now I know the box is fine so super happy!